MIMO technology has attracted attention in wireless communications as it offers significant increase in data throughput and link range without the need for additional bandwidth or increased transmit power. This increase in throughput is achieved by spreading the same total transmit power over the antennas to achieve an array gain that improves the spectral efficiency (more bits per second per hertz of bandwidth) or to achieve a diversity gain that improves the link reliability (reduced fading). Because of these properties, MIMO is an important part of modern wireless communication standards such as IEEE 802.11n (WiFi), HSPA+, 4G, 3GPP Long Term Evolution (LTE), LTE-Advanced (LTE-A), WiMAX, etc.
Multi-user MIMO or MU-MIMO is an enhanced form of MIMO technology that is gaining acceptance. MU-MIMO enables multiple independent radio terminals to access a system enhancing the communication capabilities of each individual terminal. MU-MIMO exploits the maximum system capacity by scheduling multiple users to be able to simultaneously access the same channel using the spatial degrees of freedom offered by MIMO.